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Jan l E. P. GRAY MUFFLER Filed Aug. 30 1920 Patented Jan. l, 1924,

EMMET P. GRAY, F DETROIT, MICHIGAN.

MUFFLER.

Application led August 30, 1920. Serial No. $6,918.

To all whom 'it-'may concern:

Be it known v'that I, EMMi-:r P. GRAY, a citizen of the United States, and residing at Detroit, in the county of W'ayne and State of Michi an, have invented a new and Improved Mu er, of which the following is a specification.

This invention relates to means for reducing the sounds of the exhaust of in# ternal' combustion engines, and its object is to provide a muiiler which shall have minimum diameter, which shall produce a minimum of back pressure, and which may be produced 'at low cost.

A'feature of this invention consists in the provision of two or more sheet metal tubes' one within the other. the tubes having longitudinal flanges nested together, the arrangement providing a silencing device withinfthe outer tube or shell and provid for' an iniovvA of exhaust gases at one to the silencing device and discharging tmosphere from the' structure. at the "opposite end; Further, the arrangement of 'the' tubes' vfor -the How of gases' is suchV that the gases-from' chamber to-`chnmber vof the several tubes expanding as the exhaust gases progress toward theexhaust end and resulting in a merging of the successive puffs `'receivedby the muffler so that' the 'discsle is practically' continuous and off the "of holes and inolosin types of muiers.- n "Thisf'inv'e'ntin further consists 'in closing the'rear end ofthe intermediate tube onto j the'i'nnertube, in closing the rear end of the `outer tube 'onto the intermediate tube, in forming the intermediate tube with a series its fron-t end.

It'alsoconsists in t e details of construction illustrated in the accompanying draw V .ing jand particularly pointed out in the In the eccompenying drawing, Fig. 1 is an internal combustion engine is to receive'L the exhaust gases discharged by successive exhaust impulses of the engine and to reduce the pressure and therefore the explosive force of the successive puffs whereby the same may be materially less noisy with# out production of material back pressure. My improved muiller seeks to still further reduce the noise of the exhaust gases :1nd produce a continuous flow thereof at the discharge end is practically constant, and it is to be understood further that the device may be .made in various forms and with two or more tubes. The particular form here shown is only one exemplification of .the invention.4

In-the present case I have provided three tubes 1, 2 and 3, one withinthe"other,j'all of substantially the same'lenvth, the' front ends of the tube 2 being closedendet soine distance back of the frontend of'thetub'e l, while thev front end ofthetube isfo'pen-nd at about the same distance back of 'the front end of the tube 2. The several, tubes are preferably formed 'with' longitudinal flanges 4, 5 and 6 whichfare The exhaust pipe 8 of the engine'fis preferably formed with af'collar 9 alidthe'front end of the tube 1 is g'ripped-onto-this"colnestedi-'a'nd 'secured @together with rivets 7, 3"

lar by means of a bolt IOf-'ilth'oughrfny other desired :means may" bd`rxiployed to form this connection?L The "-er end 'ofj the tube 3 is similarly gripped"'onto 'a tail 'pipe 12. The rear end of the tube 3-fisgripped by the pinched downend'foF-the tube 2.

rivets 13 being inserted f-to'se'cure. theI tubes together, while rivets -14' -siinilarlyfsecure the tube 1 onto the tube 'lvhe-itube 2 is formed with any desired number of perforations 15. l l

The cross sectional aree between the tubes 1 and 2 should bees large' and preferably one-fourth laro'er than the are'of the passage of the exhaust pipe. AIy prefer tollie've the net area of the tubel somewhat ylrger 'i A- than the net areaof -the tubeY-2anldthat somewhat larger than theneti'area of-the tube 3, twenty per cent being sufficient in each case. I prefer to make-"the len h of the tube 1 from ten to'iifteen times its' diameter, which differsv 'greatly from the presen-t types of muliers who'sef lengths are usually less than three times the diameters.

lrVhen a puff of exhaustgasesfenters this muiiier, 'e portion immediately passes through the front holes l into .the intel'H mediate tube 2 and then ,passes into the inner tube 3. As the` gases more along in the tube l, other portions pass through the 5 succeeding holes l5 and then forward in the tube 2 to the 'front end ot' the tube ,Band then rearwardly therein. As a result., by the time the gaseshave reached the-rear end of the tube l their pressure has been greatly reduced `and a substantially constant stream, of these gases has moved forward within the tube 2 lto the front end of the tube 3 and rearward therein. The back pressure created, by this mutlier is only a {ei/31 ounces and the escape of the gar-aes from the tail pipe 12 is uniform Eand almost noiseless, even when the muffler is used with high duty engines. Any usual means may be employed to prevent the radiation of heat from thefmuier, ,but the layer of asbestos between two sheets of'steel which are used to form outer shells of many mulliers in order to deaden the drumming `noise of the puiis. of theieidiaust` when it enters the mulilers .willvordinarily' Ebe ffound unnecessary, especially f when,v there fis suilicient space to build Vthewpresent muiller of properF length. ably in Vtwo rows `which are diametrically opposite-each other and equal distancesrom thepjlanges 5, tand; theirf combined area is .somewhat greaterfthan the net `aremof thev V- pige L' n orderfgto. prevent carbon irqm ,lodging 1 E inptl'ie firent 4:endg of 4the intermediate; tube t ,I may makez use` of tubea distance l from, the-end 4 thereof, ,said

and between the tubes,

. -anjector-for causing armere-rapid lflow of es gases through Vthe inneritubewyTo thiseend 'LmountLaxsmall pipe llfin the closed front 40 end ofthetube- 2,; the front endof the pipe Vflt4 i being preferably enlarged andi the. 4rear end fre'ducedpwhich pipeis in thexline ofthe Ve;.i:l1aust ipeV Sivand thus `receives gases-at inner 'andintermediate tubes, theintermedi-.a

ate :tubebein -the innerltu having a closed, foliiiifJi-I4-ll` end, ,the `opposite 1 ,Vihilell` have; shown-the tubes to be cylindrieal,'I do-notwishftofbe limited thereto asvthefform of thesetubes and thefcther details -of the mullier may all bechaiged byt'those Skilled in theart Without departing from the spirit of my invention as .set `forth vtheifoltowing claims. I-nstead .'ofhaving the flanges 4, 5 and' 6 on the lowenside of' the-muler they may extend up orin any other direction andthe vznulllerfmayl be inclined at anyangle which maybe-found most desirable.

As previously stated, one ofthe main Vfeatures of this1 invention is in the supporting of onetube vwithin another by nesting .of theflan'ges and'fwhile an inner, outer and intermediate tube have been shown arranged to; produce apractically continuous flow of gas from .the discharge endy at practically constant pressure, itis to'vbe understood 05 -thatthe invention-as set forth 4,in -theapttrontends of the other. tuvo. f The holes l5 areprefer- 'inner and intermediatetubes,the intermedi,-g;i

. he central portions `off which areyin ,pended claims may beernbodied in a l( rm and arrangement of the tubes other than is shown by the drawing.

l claim:

l. In a' muier, the combination of outer, 70 inner and intermediate tubes, the intermediate tube beiner within the outer and without .the in-neigt, e. .and being perforated and having a closed forward end, the oppositf` end of the intermediate Atube being closed 75 around the inner tube a distance from the end thereof and the saine end of the outer tube being closed around the intermediate tube a distance from the end thereof.

251m a muffler, the combination fof outer, inner and intermediate tubes, the .intermediate tube being With-in the outer and, without the inner tube and being perforated. Iand having a closed forward end,Y the QPPOSite Vend ot' the intermediate tube being closed 85 ,around the inner tube and thesam'e end of `the outer tube beingclosed laroundthe intermediate tube, the rontopen end of the -inner tube being@ distancerom :the lfront. .end of the 4outer tube and. `thefront` end of 00 the intermediate tube.I being .between the 3. Inla muiiler, the combination'oift outer,

ate tube bein within the outervandovithout having `a,- -closed lforward en the opposite end of the intermediatev'tube lbeing ,closed around the inner! Atube ia .distance liront the y end thereof andithefsame endeo cithe outer tube tbeing. closed around -tlie :intermediate tubes 4being -formedlofstrips of, sheegrnetal,

. alan; ormv .and the edgesonsttuting; parallel ,ianges which-,are faiestedqand `r:secured together.

1 4.1In va muler,

ilili'fi AIn the combi .twin 0f l eviter,

4,within A, the outer, ,and av' thout 1 10 eend beirigperforat 'fand end of' the intermediate italie-.being closed around. the innerttubea ,distance,froml the the-inner tu eandbeing :perforated 'and having a closed forwardgend, theopposite end of the outer .tube beingclosed yto ,prevent the escapeof gases therefrom, andan lejector tube mountedd-ntheV closed forward end-of theiintermediate tube and-extending 1 rearwardly ,tothe inner .tube tofconduct ases from the front end of the outer tube directly into the front end of the inner tube.

6. In a mulller, the combination of inner and outer tubes formed of sheet metal, the central portions of which are ltubular in form and each provided with a longitudinal flange, the flange of the inner tube being nested in and secured to the flange of the outer tube. i...

7. In a. muiiler, the combination of outer and inner members, the central portion of each member being curved and the edges of each member constituting parallel outwardly extending flanges, the flanges of the two members being nested and secured together.

8. A muffler comprising an interior silencing device having Van outwardlwy extending rib, and a shell enclosin said silencing device and having lon 'tu inal edges extend ing outwardly and tting against and over the rib on the interior member.

9. A muiller and a pipe extending into one end thereof, said mufiler having a shell formed of sheet metal which is bent around the pipe and having the two edges outwardly bent in parallel relation roviding a flange and an external shell oi) sheet metal of greater diameter positioned thereabout and having similar flanges engaging the flange of the first named shell, the flanges of the two shells being secured together.

10. A muflier comprising a tubular metallic shell adapted to receive a pipe of less diameter in one end, said end being flattened in part to cause the metal to fit around the pipe.

11. In a mufiler, the combination of an interior silencing device having an exterior longitudinal radial rib, and a shell connected with said silencing device and formed with a longitudinal radial rib embracing and fitting against the rib on the interior member.

12. A muffler comprising an exterior tubular shell formed to provide an external longitudinal flange, an inner tubular silencing member having an external longitudinal flange fitting and secured to the flange of the outer member, providing a closed seam, the parts being so arranged at one end to fit an exhaust pipe discharging into the silencing member and opening at the opposite end to atmosphere.

13. A mutller com rising an exterior shell formed of a sheet o metal, the edges being brought together and outturned providin a longitudinal flange, an inner silencing evice provided with a flange secured to the flange of the outer shell, the devices being arranged to provide an inflow of exhaust gases at one end to the silencing device and to discharge from the outer member at the opposite end.

14. A muliler comprising an exterior shell formed of sheet metal folded in tubular form with the edges outwardly extending providing a longitudinal rib, a tubular silencing device within the outer member `formed ot sheet metal having an external flange extending between the outwardly extending rib parts of the outervmember and secured therebetween, the arrangement providing for a How of gases from one end to the other of the device.

15. A mulller comprising a series of shells` of tubular form each formed of a sheet of metal and shaped to provide a longitudinal rib, the said shells being one within the other and apertured to provide communication successively one to the other, the ribs of the several shells being nested together and secured in position, and a pipe leadin into the shell of least diameter at one en the shell of larger diameter opening to atmosphere at the opposite end.

16. A muffler comprising an exterior tubular member of sheet metal having an outwardly extending longitudinal flange of two spaced parts, an inner silencing member also having a longitudinal flange nesting in and Supporting between the flange parts of the outer member closing the same to atmosphere, the arrangement providing a device adapted for attachment to an exhaust pipe at one end and to discharge to atmosphere at the opposite end.

17. A mu er comprising an outer tubular shell, edge portions of which are outturned and spaced providing external longitudinal flanges, a tubular sheet metal silencing device therewithin also provided with a flange positioned between the flanges of the outer shell, the parts being arranged to receive exhaust gases at one end and discharge the same from the other end only of the structure, and means intermediate the ends gases to pass successively from causing the of one member to the interior of sheet metal having longitudinal flangesV at one side formed by the outwardly extending edges of the sheet forming the shell, an interior silencin device of tubular form extending longitu inally of and less in diameter than the exterior member and having a longitudinal flange nesting in and secured to the flanges of the exterior member, the inner member having a series of apertures therein, and means between the members whereby gases passing into the exterior member are passed into the interior member before dischar e from the muflier, the structure being a apted for connection to an exhaust piping at one end and discharging to atmosphere at the opposite end only.

19. A mufiler comprising an interior silencing device having an outwardly extending rib, and a shell enclosing said silene ingr device and having its longitudinal edges extending outwardly and fitting against nml over the rib on the interior member.

20. A mulHer comprising :i tuhului' shell adapted to receive n pipe of less diameter in one end, said end being flattened in part; to cause the metal to fit around the pipe.

21. In :a muliler7 the combination of :in

interior silencing device having an exterior longitudinal radial rib, and a Strip Aformed into a tube t0 surround said silencing device and having an outwardly projecting longitudinal rib fitting over the rib 0n the interior member.

EMMET P. GRAY. 

